Project Summary Female sex workers (FSW) bear a disproportionate burden of depression and post-traumatic stress disorder (PTSD) compared to the general female population. There is some evidence of the role of structural vulnerabilities (i.e. homelessness, stigma, poverty) in poor mental health in the general population however there has been little research on the nature of this relationship FSW, a population that is characterized by a diverse array of structural vulnerabilities. Resilience has played a promising role in improving mental health in prior research yet it is unclear the role it may play for FSW. The proposed mentored research will examine patterns of structural vulnerabilities among a sample of FSW in Baltimore, Maryland collected at baseline (n=350) and how resilience moderates the relationship between these patterns and mental health at 12-month follow-up. Semi-structured in-depth interviews with free listing will be used to qualitatively examine how women (n=20-25) describe dimensions and experiences of resilience in their lives and how they acquire resources to strengthen resilience, including social support. (Aim 1). Using baseline survey data, latent class analysis (LCA) will be performed to determine patterns of structural vulnerabilities (Aim 2). Then, LCA with distal outcomes will be used to predict mental health (depression, PTSD, and co-occurring PTSD and depression) at 12-month follow-up based on structural vulnerability class (Aim 3). Finally, LCA models with distal outcomes will be used to explore the moderating role of resilience in the relationship between structural vulnerability class and mental health (Sub-aim 3a). This study uses a novel mixed methods approach to explore moderating factors that influence mental health among a population that experiences high rates of mental illness and structural vulnerabilities. Findings can elucidate the drivers of the mental health disparity between FSW and the general population. Results can also inform clinical and research interventions for addressing social and structural-level risks and protective factors among a vulnerable population. This project will prepare the applicant to become a leading independent researcher in the fields of mental health among vulnerable populations. The culminating results from this project can help NIMH meet Strategic Objectives 2, 3, and 4 by using advanced LCA methods to predict classes of risk factors for PTSD and depression in a sample of women who experience significant mental health disparities; these risk factor classes can better inform mental health prevention and clinical care.